Evolutional principles of homology in regulatory genes of myogenesis

Abstract

Analysis of early steps in muscular system development of invertebrates and vertebrates shows that early steps of myogenesis are regulated by genes-orthologs mainly belonging to two families, Pax and bHLH. In the majority of the following organisms, muscles formation (steps of determination and the earliest steps of myogenesis) is regulated by genes orthologs Pax3 which belong to the family Pax: nematodes (Caenorhab ditis elegans, Pristionchus pacificus), insects (Drosophila melanogaster), echinoderms (Strongylocentrotus pur puratus), sea squirts (Ciona intestinalis, Holocynthia roretzi), fishes (Danio rerio), amphibians (Xenopus lae vis), birds, and mammals (mouse, rat). The nematode C. elegans is an exception since formation of its muscles in this period is regulated by homeobox gene Pal 1 belonging to the family Caudal. The sea squirt C. intesti nalis is also an exception because the earliest steps of development involved in further muscle formation are accompanied by activation of the gene CiSna (snail) (gene family basic Zinc finger). The next steps of myo genesis in all analyzed species are regulated by genes orthologs belonging to the family of transcriptional fac tors bHLH. They along with genes Pax3 are characterized by a high extent of homology in all studied groups of animals.

Myogenic regulatory factors: The orchestrators of myogenesis after 30 years of discovery

“…16 It is, however, the bHLH domain that is considered the main contributor to myogenesis activation. 17 The bHLH domain has been found in MRFs of many different species, such as humans, rodents, avian, and xenopus. 16 In general, there are seven classes of HLH proteins.…”

Convergence of stem cell behaviors and genetic regulation between animals and plants: insights from the Arabidopsis thaliana stomatal lineage

“…In stomatal development, there is a correspondence between the number of discrete steps in the pathway to make stomata and the number of group Ia bHLHs, with the FAMA-driven differentiation function most likely the ancestral function and the asymmetric-division promoting activity of SPCH being a later addition [ 78 , 79 ]. The four myogenic regulatory factors (Myf5, MyoD, myogenin, and MRF4) arose from vertebrate-specific duplications [ 80 , 81 ]. The invertebrates Caenorhabditis elegans and Drosophila have single MyoD orthologs and relatively simple muscle lineages, with Drosophila not maintaining stem cells in adults and C. elegans lacking stem cells altogether [ 82 ].…”